Steel 6152 · heat-treated state
Steel 6152 Q&T
Properties of the Q&T condition, compared with the other 6152 tempers.
General-purpose high-strength condition for torsion bars, shafts and heavy springs balancing strength with toughness.
What is 6152 Q&T?
6152 Q&T is 6152 heat treated to Q&T — general-purpose high-strength condition for torsion bars, shafts and heavy springs balancing strength with toughness. 6152 Q&T has a yield strength of 1,180 MPa (171 ksi) and a tensile strength of 1,300 MPa (189 ksi) — stronger than 94% of steel grades. Elongation at break is 12% and the elastic modulus is 207 GPa (30 Msi). 6152 Q&T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). Annealed is the default condition FabDigit quotes; Q&T is available on request or by drawing note.
Advantages
- High strength — 1,180 MPa (171 ksi), better than 94% of steel grades
Limitations
- Limited formability — 10/100, worse than 94% of steel grades
- Difficult to machine — 28/100, worse than 91% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Difficult to weld — 25/100, worse than 77% of steel grades
6152 Q&T properties
Typical room-temperature values for 6152 Q&T — 15 properties are specific to this condition; the rest are grade-level values shared by every 6152 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
6152 Q&T has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical13
6152 Q&T has a yield strength of 1,180 MPa (171 ksi) and a tensile strength of 1,300 MPa (189 ksi) — stronger than 94% of steel grades. Elongation at break is 12% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
6152 Q&T is rated for continuous service to 380°C (716 °F). It conducts heat at 43 W/m·K (24.8 BTU/hr·ft·°F), better than 51% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
6152 Q&T conducts electricity at 7.5 % IACS, worse than 68% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of 6152 Q&T takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 35%.
Manufacturability8
6152 Q&T's machinability is poor (28/100, worse than 91% of steel grades); weldability poor (25/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 6152 tempers and conditions
6152 is also supplied in 5 other conditions. The full side-by-side table is on the 6152 overview.
- AnnealedDefaultPick for machining, cold forming or coiling before final hardening; lowest strength, best workability.415 MPa yield · 197 HB
- Hardened & TemperedPick for leaf/coil springs and hand tools needing maximum elastic limit and fatigue strength at reduced ductility.1,450 MPa yield · 48 HRC
- Q&TGeneral-purpose high-strength condition for torsion bars, shafts and heavy springs balancing strength with toughness.1,180 MPa yield · 42 HRC
- NormalizedPick for a uniform fine-grained structure and mid-range strength before hardening, or for as-supplied hot-rolled bar refinement.615 MPa yield · 27 HRC
Working with 6152 Q&T
Is 6152 easy to machine?
Machine in the annealed or normalized state (≈55 % of 1212); above ~40 HRC use carbide or CBN, rigid setups and light finishing passes, and expect grinding for final tolerances.
Can 6152 be welded?
Not recommended for structural joints — preheat 250–350 °C, low-hydrogen consumables and immediate post-weld temper are mandatory to avoid HAZ cracking; never weld in the spring-tempered condition.
Can 6152 be formed, bent or molded?
Cold coil, bend or blank in the annealed condition then harden; hot forming 950–1150 °C followed by full quench-and-temper gives the best spring properties.
What surface finishes work on 6152?
Not stainless: phosphate-and-oil, black oxide, shot peen (strongly recommended for fatigue), zinc or paint; avoid acid pickling/electroplating at high hardness or bake out hydrogen after plating.
6152 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Colder SAE 6152 range; modern 6150 is 0.48–0.53 | 0.45 – 0.55 | 0.5 |
| Mn | 0.6 – 0.9 | 0.75 |
| Si | 0.15 – 0.35 | 0.25 |
| Cr | 0.8 – 1.1 | 0.95 |
| V0.15 % min per SAE | 0.15 – 0.25 | 0.18 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
6152 Q&T — frequently asked
What is 6152 Q&T used for?
6152 Q&T is typically used for heavy leaf springs, coil springs, torsion bars, truck and trailer suspension springs, spring clips and retainers and agricultural tines and tillage parts. In short: vanadium spring-steel bar.
What is the yield strength of 6152 Q&T?
6152 Q&T has a typical yield strength of 1,180 MPa (171 ksi) and a tensile strength of 1,300 MPa (189 ksi) — stronger than 94% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 6152 Q&T easy to machine?
Not especially — machinability is rated poor (28/100, worse than 91% of steel grades). Machine in the annealed or normalized state (≈55 % of 1212); above ~40 HRC use carbide or CBN, rigid setups and light finishing passes, and expect grinding for final tolerances.
Can 6152 Q&T be welded?
Not readily — weldability is rated poor (25/100). Not recommended for structural joints — preheat 250–350 °C, low-hydrogen consumables and immediate post-weld temper are mandatory to avoid HAZ cracking; never weld in the spring-tempered condition.
What surface finishes work on 6152 Q&T?
Not stainless: phosphate-and-oil, black oxide, shot peen (strongly recommended for fatigue), zinc or paint; avoid acid pickling/electroplating at high hardness or bake out hydrogen after plating.
Can 6152 Q&T be formed, bent or molded?
Cold coil, bend or blank in the annealed condition then harden; hot forming 950–1150 °C followed by full quench-and-temper gives the best spring properties.
What is the maximum service temperature of 6152 Q&T?
6152 Q&T is rated for continuous use to about 380°C (716 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 6152 Q&T?
Yes — 6152 Q&T is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- ASTM A231/A232 — Chromium-Vanadium Alloy Steel Spring Wire — ASTM (2020)
- EN 10089 — Hot-rolled steels for quenched and tempered springs (50CrV4 / 1.8159) — CEN (2002)
- GB/T 1222 — (50CrVA) — SAC (2016)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating — ASM International (1991)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.